docs: def readline(self):
          """
          Read and return a line of text.
  
          :rtype: str
          :return: the next line of text in the file, including the
            newline character
          """
          _complain_ifclosed(self.closed)
          line = self.f.readline()
          if self.__encoding:
              return line.decode(self.__encoding, self.__errors)
          else:
              return line